Each failure presented at each level is represented with ‘holes’ in the cheese. The active failures are typically the last unsafe acts committed by aircrew. The Swiss cheese model is useful to investigators because it forces them to go beyond active failures of crew members and to investigate latent failures preceding the accident as well. As their name suggests, latent failures, unlike their active counterparts, may lie dormant or undetected for hours, days, weeks, or even longer, until one day they adversely affect the unsuspecting aircrew, and consequently, they may be overlooked by investigators with even the best intentions (Shappell & Wiegmann, 2000, p. 2).
In the case of the Tenerife disaster, different contributing factors leading up to this crash can be identified. The primary example of an outside/organizational influence surrounding this accident were the duty limiting restrictions which placed added pressure on the KLM captain to take off quickly. These restrictions have been in place since the 1940’s and were implemented to reduce fatigue by ensuring crews are provided adequate time for rest (Department of Transportation, 2010, p. 1). In this case, had there been no duty limiting restrictions to influence decisions of the KLM crew, this situation may have resulted in a different outcome.
There were additionally several preconditions for unsafe acts which placed the aircraft and personnel in an unsafe condition. These preconditional factors included: The bomb incident in Las Palmas which forced aircraft to divert to other locations, the incoming fog that caused rapid changes in visibility on the airfield, the refuelling of the KLM aircraft that caused delays for airfield traffic, abnormal airfield congestion led to non-standard taxiing procedures and maneuvers, the inability of the Pan Am crew to correctly locate the location to exit the runway, the communication factors between the KLM pilot and ATC regarding aircraft take-off, and radio transmission interference which caused the KLM crew to not clearly hear communications from Pan Am and ATC (Cookson, 2009, p. 22.9).
This chain of events then ultimately lead to the unsafe acts causing the accident. The primary examples of unsafe acts were: The KLM captain taking off without proper ATC clearance, the KLM captain not obeying the ATC standby instructions, the KLM captain not interrupting take-off when the Pan Am crew reported they were still taxiing down the runway, and the KLM crew not clearly stating the Pan Am flight was still on the runway at the time of take-off (Cookson, 2009, p. 22.9). The decision of the KLM captain to take-off despite given uncertainties is one example of unsafe supervision which allowed the unsafe acts to occur. Had any member of the crew provided the proper guidance or leadership prior to take-off this accident could have been avoided.
Recommendations. To date, this crash remains the single deadliest aircraft accident ever, claiming the lives of 583 people. In order to minimize the possibility of recurrences, a global aviation communication standardization would be imperative. This accident forced aviation authorities to implement comprehensive changes to international airline regulations by mandating that all control towers and flight crews across the globe use standardized English phrases (Roitsch, Babcock, & Edmunds, 1978, p. 27). Cockpit procedures were also adapted to ensure decisions were made by a mutual agreement in the cockpit instead of placing sole authority on the highest ranking individual (Roitsch, Babcock, & Edmunds, 1978, p. 27). This new concept would then be known in the aviation industry as crew resource management (CRM) and be adopted worldwide.
The development of CRM cannot be attributed to the Tenerife accident alone, but this accident in conjunction with various other major aviation accidents throughout the 1970’s played a major role in the requirement of aviation policy changes. Modern CRM theory accepts that human errors are inevitable, and therefore, CRM practices should serve as a set of counter-measures with three distinct lines of defence: Error avoidance, trapping errors before they are committed, and mitigating the consequences of those human errors which occur and are not trapped (Rodrigues & Cusick, 2012, p. 166). Although a monetary sum of revenue from CRM practices does not exist, the benefits have been proven through successful examples of using this concept. One of the most vivid examples was the landing of UA Flight 232 in Sioux City, IA in 1989. Through principles of CRM, the captain of this flight effectively used all available resources to extraordinarily land the aircraft with a total loss of hydraulic power thereby saving 185 lives (Rodrigues & Cusick, 2012, p. 165).
In conclusion, the single worst aviation accident in history would reveal multiple shortcomings that would forever change policies, communications, and operations in aviation. The Tenerife accident contained several examples of poor decision making influenced by outside factors and communication misinterpretations leading to confusion and false assumptions. Two of the primary examples include taking off without clearance and not confirming radio communications. Although human factors may be an unavoidable phenomenon, each aviation accident must be used as an opportunity to improve safety and prevent deaths through technological advancements, process and policy changes, and training. Had such policies such as CRM and communication standardization been contemplated, the 583 people who perished on Tenerife may still be alive. For this reason safety tools such as the Swiss cheese model of accident causation and crew resource management have been developed to help experts and industry professionals identify and alleviate deficiencies before accidents occur. Since the 1960’s, aircraft accidents have been reduced by 30% but nevertheless each individual accident represents its own unique call to action (Boeing, 2014, p. 14). Each corrective measure brings man one step closer to eliminating human error and further decreasing aviation accidents.
...(download the rest of the essay above)